Grafted polymer with soot handling properties

ABSTRACT

The present disclosure relates to viscosity index modifiers that have dispersant properties and lubricating oil compositions comprising said viscosity index modifiers. The viscosity index modifier is the reaction product of an acylated olefin copolymer, a polyamine, and a dicarboxylic acid or anhydride thereof that can react with a free primary amine of the polyamine to form a ring moiety. The disclosure also relates to the use of lubricant compositions comprising the viscosity index improvers of the disclosure for improving the soot or sludge handling characteristics of an engine lubricant composition, while minimizing the deterioration of engine seals.

TECHNICAL FIELD

The present disclosure relates to viscosity index modifiers that havedispersant properties, additive concentrates thereof, and lubricatingoil compositions comprising such dispersant viscosity index modifiersand concentrates. The disclosure also relates to the use of lubricantcompositions comprising the dispersant viscosity index improvers hereinfor improving soot or sludge handling characteristics of an enginelubricant composition while minimizing the deterioration of engine sealsat the same time.

BACKGROUND

An engine lubricant provides increased engine protection tending toimprove fuel economy and reduce emissions. However, it is generallyundesired to sacrifice engine protection and lubricating properties toachieve the benefits of improved fuel economy and reduced emissions, andmost lubricants often find a balance between such properties. Forexample, an increase in the amount of friction modifiers in thelubricant may be beneficial for fuel economy purposes but may lead toreduced ability of the lubricant to handle wear stresses imposed byexternal contaminants, such as water. Likewise, an increase in theamount of anti-wear agent in the lubricant may provide improved engineprotection against wear, but could also increase emissions throughvarious mechanisms, such as being detrimental to catalyst performance.

Likewise, soot and sludge handling components of the lubricant mustachieve a similar balance. For example, the soot and sludge handlingproperties of the lubricant are often improved as the amount ofdispersant in the lubricant is increased, but increasing the amount ofdispersant can adversely affect elastomer compatibility. This can happensince dispersants are typically amine-containing-compounds that aredetrimental to seals. Introducing polyaromatic functionality into adispersant improves the dispersant's ability to control viscosityincreases in a lubricating oil characteristic of soot contamination.Accordingly dispersants reacted with an aromatic anhydride and cappedwith a cyclic carbonate are believed to provide better soot handlingcapabilities than conventional dispersants. However, such functionalizeddispersants often exhibit poor elastomer compatibility even atrelatively low treat rates.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a graph of viscosity (Pa-s) versus shear rate (1/s) forevaluating soot dispersancy of compositions herein.

SUMMARY

In one aspect, a highly grafted, multi-functional olefin copolymerviscosity modifier is described. The viscosity modifier includes areaction product of (a) an acylated olefin copolymer including an olefincopolymer having grafted thereon from 0.10 to 0.80 acyl groups per 1000number average molecular weight units of olefin copolymer and whereinthe olefin copolymer has a number average molecular weight of betweenabout 500 and 100,000 (and in other approaches, about 500 to about40,000); (b) a polyamine compound of Formula I:

andc) a dicarboxylic acid or anhydride thereof, which can react with a freeprimary amine of Formula I to produce a ring moiety A

wherein ring moiety A is a 5, 6, or 7 membered heterocyclic ring havingup to three rings fused thereon, wherein the ring or rings fused thereonare selected from phenyl, carbocyclic, heterocyclic, heteroaryl, orcombinations thereof, and wherein ring A is optionally substituted withone or more substituents selected from halo, —CN, oxo, hydroxyl,haloalkyl, C₁₋₄ alkyl, C₁₋₄ alkylcarbonyl, C₁₋₄ alkoxy, C₁₋₄alkoxycarbonyl, —NH₂, —NH(C₁₋₄ alkyl), and N(C₁₋₄ alkyl)₂. In Formula I,X is a C₂ to C₅₀ alkylene linker unit wherein one or more carbon unitsare optionally and independently replaced with a bivalent moietyselected from the group consisting of —O—, —NR′—, —NR′—, —C(O)—,—C(O)O—, —C(O)NR′, and wherein each X is optionally and independentlysubstituted with one or more R″ substituents; each R′ is selected fromthe group consisting of hydrogen or C₁₋₆ aliphatic, phenyl, oralkylphenyl; and each R″ is independently selected from the groupconsisting of C₁₋₆ aliphatic, C₃₋₇ cycloalkyl, a 3-7 memberedheterocycloalkyl, heteroaryl, and phenyl, wherein R″ is optionallysubstituted with halo, cyano, amino, hydroxyl, —OR′, —C(O)R′, —C(O)OR′,or —C(O)NR′₂.

In some embodiments of the aspect from the previous paragraph, X is apolyalkylamine unit of the formula, -(alkylene-NR′)_(n)-alkylene-, andwherein the alkylene moieties are C₁-C₆ branched or straight alkylenemoieties, and n is an integer from 1 to 20; and/or X is

and/or X is a polyalkylene glycol unit of the formula,-(alkylene-O)_(m)-alkylene-, and the alkylene moieties are C₁-C₆branched or straight alkylene moieties, and m is an integer from 1 to50; and/or X is a moiety to form a polyether diamine; and/or whereinring moiety A is

and/or wherein the olefin copolymer is a copolymer of ethylene and analkylene having 3 to 18 carbon atoms; and/or wherein the olefincopolymer has a number average molecular weight of about 500 to about20,000; and/or wherein the acyl groups grafted on to the olefincopolymer are obtained from acyl reactants that include at least onecarbon-carbon double bond and further comprise at least one carboxylicacid and/or dicarboxylic anhydride group; and/or wherein the olefincopolymer has grafted thereon from 0.2 to 0.5 acyl groups per 1000number average molecular weight units of olefin copolymer.

Another aspect of the present disclosure includes an additiveconcentrate including the highly grafted, multi-functional olefincopolymer viscosity modifier as described in the prior two paragraphs.In some approaches, the additive concentrate may include about 10 toabout 60 weight percent of the highly grafted, multi-functional olefincopolymer viscosity modifier in a diluent oil.

In yet another aspect of this disclosure, a lubricating oil compositionis provided. The lubricating oil composition includes a major amount ofa base oil and a highly grafted, multi-functional olefin copolymerviscosity modifier. In some approaches the high grafted,multi-functional olefin copolymer viscosity modifier includes thereaction product of (a) an acylated olefin copolymer comprising anolefin copolymer having grafted thereon from 0.10 to 0.80 acyl groupsper 1000 number average molecular weight units of olefin copolymer andwherein the olefin copolymer has a number average molecular weight ofbetween about 500 and 100,000 (in other approaches, about 500 to about40,000); (b) a polyamine compound of Formula I:

and(c) a dicarboxylic acid or anhydride thereof, which can react with afree primary amine of Formula I to produce a ring moiety A

wherein ring moiety A is a 5, 6, or 7 membered heterocyclic ring havingup to three rings fused thereon, wherein the ring or rings fused thereonare selected from phenyl, carbocyclic, heterocyclic, heteroaryl, orcombinations thereof, and wherein ring A is optionally substituted withone or more substituents selected from halo, —CN, oxo, hydroxyl,haloalkyl, C₁₋₄ alkyl, C₁₋₄ alkylcarbonyl, C₁₋₄ alkoxy, C₁₋₄alkoxycarbonyl, —NH₂, —NH(C₁₋₄ alkyl), and N(C₁₋₄ alkyl)₂. In Formula 1,X is a C₂ to C₅₀ alkylene linker unit wherein one or more carbon unitsare optionally and independently replaced with a bivalent moietyselected from the group consisting of —O—, —NR′—, —NR′NR′—, —C(O)—,—C(O)O—, —C(O)NR′, and wherein each X is optionally and independentlysubstituted with one or more R″ substituents; each R′ is selected fromthe group consisting of hydrogen, C₁₋₆ aliphatic, phenyl, oralkylphenyl; and each R″ is independently selected from the groupconsisting of C₁₋₆ aliphatic, C₃₋₇ cycloalkyl, a 3-7 memberedheterocycloalkyl, heteroaryl, and phenyl, wherein R″ is optionallysubstituted with halo, cyano, amino, hydroxyl, —OR′, —C(O)R′, —C(O)OR′,or —C(O)NR′₂.

In some embodiments of the lubricating oil composition aspect of theprevious paragraph, X is a polyalkylamine unit of the formula,-(alkylene-NR′)_(n)-alkylene-, and wherein the alkylene moieties areC₁-C₆ branched or straight alkylene moieties, and n is an integer from 1to 20; and/or X is

and/or X is a polyalkylene glycol unit of the formula,-(alkylene-O)_(m)-alkylene-, and the alkylene moieties are C₁-C₆branched or straight alkylene moieties, and m is an integer from 1 to50; and/or X is a moiety to form a polyether diamine; and/or ring A is

and/or the olefin copolymer is a copolymer of ethylene and an alkylenehaving 3 to 18 carbon atoms; and/or the olefin copolymer has a numberaverage molecular weight of about 500 to about 20,000; and/or the acylgroups grafted on to the olefin copolymer are obtained from acylreactants that include at least one carbon-carbon double bond andfurther comprise at least one carboxylic acid and/or dicarboxylicanhydride group; and/or the olefin copolymer has grafted thereon from0.2 to 0.5 acyl groups per 1000 number average molecular weight units ofolefin copolymer.

DETAILED DESCRIPTION

Engine or crankcase lubricant compositions are used in vehiclescontaining spark ignition and compression ignition engines. Such enginesmay be used in automotive, truck, and/or train applications, to suggestbut a few examples, and may be operated on fuels including, but notlimited to, gasoline, diesel, alcohol, compressed natural gas, and thelike. The lubricants or lubricant compositions herein may be suitablefor use as engine or crankcase lubricants, such as automotive crankcaselubricants that, in some circumstances, meet or exceed the ILSAC GF-5and/or API CJ-4 lubricant standards.

As noted in the background, engine oils commonly include many additives.Dispersants are a common additive to engine oil to help in diffusingsludge, carbon, soot, oxidation products, and other deposit precursors.Dispersants aid in keeping engine parts clean, prolonging engine lifeand helping to maintain proper emissions and good fuel economy. Theresult is reduced deposit formation, less oil oxidation, and lessviscosity increase. In some approaches, the dispersants accomplish thisby inhibiting particle-to-particle aggregation. Accordingly, the sootand sludge handling properties of the lubricant are improved as theamount of dispersant in the lubricant composition is increased, butincreasing the amount of dispersant can in some instances adverselyaffect elastomeric seals. Described herein, on the other hand, aredispersant viscosity index modifiers, and lubricating oils includingsuch dispersant viscosity index modifiers that have good soot handlingproperties and viscosity modifying properties and, at the same time, arealso less destructive to engine seals (that is, seal friendly) ascompared to prior lubricants and prior viscosity modifiers.

Turning to more of the specifics, a highly grafted, multi-functionalolefin copolymer viscosity modifier is described herein. In one aspect,the dispersant viscosity index modifier includes a reaction product of(a) an acylated olefin copolymer; (b) a polyamine; and (c) adicarboxylic acid or anhydride thereof that can react with primaryamines of the reaction product between the acylated olefin copolymer andthe polyamine. The selected dicarboxylic acid or anhydrides provides acapping agent of the primary amines to form a ring structure andpreferably a capping agent for a terminal primary amine. The cappedamines make the dispersant viscosity index modifiers herein more sealfriendly but permit the additive to maintain its dispersant andviscosity index properties at the same time.

In some approaches, the acylated olefin copolymer includes an olefincopolymer having grafted thereon from about 0.10 to about 0.80 acylgroups per 1000 number average molecular weight units of olefincopolymer and wherein the olefin copolymer backbone has a number averagemolecular weight of between about 500 and 100,000 (in other approaches,about 500 to about 40,000). The polyamine, in some approaches, may be acompound of Formula I:

where X is a C₂ to C₅₀ alkylene linker unit wherein one or more carbonunits thereof are optionally and independently replaced with a bivalentmoiety selected from the group consisting of —O—, —NR′—, —NR′NR′—,—C(O)—, —C(O)O—, —C(O)NR′ Each X of Formula I may be optionally andindependently substituted with one or more R″ substituents. Each R′ canbe selected from the group consisting of hydrogen or C₁₋₆ aliphatic,phenyl, or alkylphenyl; and each R″ is independently selected from thegroup consisting of C₁₋₆ aliphatic, C₃₋₇ cycloalkyl, a 3-7 memberedheterocycloalkyl, heteroaryl, and phenyl. In some approaches, R″ isoptionally substituted with halo, cyano, amino, hydroxyl, —OR′, —C(O)R′,—C(O)OR′, or —C(O)NR′₂. The dicarboxylic acid or anhydride thereof isselected so that it can react with a free primary amine of Formula I toproduce a ring moiety A

wherein ring moiety A is a 5, 6, or 7 membered heterocyclic ring havingup to three rings fused thereon. The ring or rings fused thereon may beselected from phenyl, carbocyclic, heterocyclic, heteroaryl, orcombinations thereof, and wherein ring A is optionally substituted withone or more substituents selected from halo, —CN, oxo, hydroxyl,haloalkyl, C₁₋₄ alkyl, C₁₋₄ alkylcarbonyl, C₁₋₄ alkoxy, C₁₋₄alkoxycarbonyl, —NH₂, —NH(C₁₋₄ alkyl), and N(C₁₋₄ alkyl)₂.

Polyamine: In some embodiments of Formula I, X may be a polyalkylamineunit of the formula, -(alkylene-NR′)_(n)-alkylene- and wherein R′ isdefined herein. The alkylene moieties may be C₁-C₆ branched or straightalkylene moieties, and n may be an integer from 1 to 20, for example, 1to 10, 2 to 8, 2 to 6, or 2 to 4 or other ranges defined within theendpoints 1 and 20. In another approaches, the alkylene moieties of areethyl, propyl, isopropyl, butyl, or isobutyl. In a further embodiment,the alkylene moieties are ethyl. In another further embodiment, thealkylene moieties are isopropyl.

In other approaches of Formula I, X is a polyalkylene glycol unit of theformula, -(alkylene-O)_(m)-alkylene- and the alkylene moieties are C₁-C₆branched or straight alkylene moieties, and m is an integer from 1 to50, for example 1 to 30, 1 to 20, 1 to 15, 1 to 10, 1 to 5, 1 to 3, 5 to10, 10 to 20, 20 to 30, 30 to 40, or 40 to 50. The alkylene moieties maybe ethyl, propyl, isopropyl, butyl, or isobutyl. In a furtherembodiment, the alkylene moieties are ethyl. In another furtherembodiment, the alkylene moieties are isopropyl. In one approach, X is amoiety to form a polyether diamine.

Each R′ of Formula 1 may be independently selected from the groupconsisting of hydrogen, C₁₋₆ aliphatic, phenyl, or alkylphenyl. In otherembodiments, each R′ is independently selected from the group consistingof hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,tert-butyl, n-pentyl, isopentyl, neopentyl, phenyl, and benzyl. In afurther embodiment, each R′ is independently selected from the groupconsisting of hydrogen, methyl, ethyl, phenyl, and benzyl. In anotherfurther embodiment, each R′ is independently selected from the groupconsisting of hydrogen, methyl, and benzyl. In still another furtherembodiment, each R′ is independently selected from the group consistingof hydrogen and methyl. In another embodiment, each R′ is hydrogen.

Each R″ may be independently selected from the group consisting of C₃₋₇cycloalkyl, a 3-7 membered heterocycloalkyl, heteroaryl, and phenyl,wherein R″ is optionally substituted with halo, cyano, amino, hydroxyl,—OR′, —C(O)R′, —C(O)OR′, or —C(O)NR′₂. In some embodiments of Formula I,each R″ is independently selected from the group consisting ofcyclopropyl, cyclopentyl, pyrrolyl, pyridyl, pyrimidyl, piperidyl,morpholino, and phenyl. In some embodiments of Formula I, each R″ isindependently selected from the group consisting of cyclopropyl,morpholino, and phenyl. In some embodiments, R″ is unsubstituted.

Numerous polyamines can be used as the polyamine of Formula 1 inpreparing the functionalized dispersant viscosity index modifier.Non-limiting exemplary polyamines may include aminoguanidine bicarbonate(AGBC), diethylene triamine (DETA), triethylene tetramine (TETA),tetraethylene pentamine (TEPA), pentaethylene hexamine (PEHA) and heavypolyamines. A heavy polyamine may comprise a mixture ofpolyalkylenepolyamines having small amounts of lower polyamine oligomerssuch as TEPA and PEHA, but primarily oligomers having seven or morenitrogen atoms, two or more primary amines per molecule, and moreextensive branching than conventional polyamine mixtures. Additionalnon-limiting polyamines which may be used to prepare thehydrocarbyl-substituted succinimide dispersant are disclosed in U.S.Pat. No. 6,548,458, the disclosure of which is incorporated herein byreference in its entirety. In an embodiment of the disclosure, thepolyamine may be selected from tetraethylene pentamine (TEPA).

Amine Capping Agent: The reaction product of the acylated olefincopolymer and polyamine may further be reacted with a dicarboxylic acidor anhydride thereof that can react with a free primary amine of theformed copolymer/polyamine product to form a ring moiety A as describedabove to cap primary amines. In one approach, the formed ring moiety Ais a 5, 6, or 7 membered heterocyclic ring having up to three ringsfused thereon, wherein the ring or rings fused thereon are selected fromphenyl, naphthyl, furyl, thiophenyl, 2H-pyrrolyl, pyrrolyl, oxazolyl,thazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl,1,3,4-thiadiazolyl, 2H-pyranyl, 4-H-pranyl, pyridyl, pyridazyl,pyrimidyl, pyrazolyl, pyrazyl, or 1,3,5-triazyl, or combinationsthereof, and wherein ring A is optionally substituted with one or moresubstituents selected from halo, oxo, hydroxyl, C₁₋₄ alkyl, or —NH₂. Inother approaches, the ring moiety A is unsubstituted. In furtherapproaches, the capping agent is selected to form the ring moiety A fromthe following ring structures wherein the linking nitrogen is part ofthe polyamine:

In some approaches, the capping agent may be selected from carboxyl orpolycarboxyl acid or polyanhydride wherein the carboxyl acid oranhydride functionalities are directly fused to an aromatic group. Suchcarboxyl-containing aromatic compound may be selected from1,8-naphthalic acid or anhydride and 1,2-naphthalenedicarboxylic acid oranhydride, 2,3-dicaroxylic acid or anhydride,naphthalene-1,4-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid,phthalic anhydride, pyromellitic anhydride, 1,2,4-benzene tricarboxylicacid anhydride, diphenic acid or anhydride, 2,3-pyridine dicarboxylicacid or anhydride, 3,4-pyridine dicarboxylic acid or anhydride,1,4,5,8-naphthalenetetracarboxylic acid or anhydride,perylene-3,4,9,10-tetracarboxylic anhydride, pyrene dicarboxlic acid oranhydride, and alike.

Capping of available primary and/or secondary amines (and preferablyterminal primary and/or secondary amines) may be up to 100 percent ofthe available primary and/or secondary amines to be capped. In otherapproaches, capping may be about 50 percent to about 100 percent. Tothis end, the moles of the capping agent reacted per mole of the primaryand/or secondary amine may range from about 0.5 to about 1.5, in otherapproaches, about 0.8 to about 1; and in yet further approaches,about 1. Preferred reaction conditions for the capping is a temperatureof about 140° C. to about 170° C. In one approach, the capping is aterminal primary and/or secondary amine. In some approaches, secondaryamines may also be capped with other compounds such as maleic anhydrideand the like.

Acylated Olefin Copolymer: The olefin copolymer, in one approach, is acopolymer backbone of ethylene and an alkylene having 3 to 18 carbonatoms, for example 3 to 6, 3 to 10, 3 to 15, 5 to 10, 8 to 12, 10 to 15,or 10 to 18. In some approaches, the alkylene may be propylene,isopropylene, butylene, isobutylene, n-pentylene, isopentylene, and/orneopentylene, and mixtures thereof.

In some approaches, polymers are copolymers of ethylene and one or moreC₃ to C₁₈ alpha-olefins. Copolymers of ethylene and propylene are mostpreferred. Other alpha-olefins suitable in place of propylene to formthe copolymer or to be used in combination with ethylene and propyleneto form a terpolymer include 1-butene, 1-pentene, 1-hexene, 1-octene andstyrene; aw-diolefins such as 1,5-hexadiene, 1,6-heptadiene,1,7-octadiene; branched chain alpha-olefins such as4-methylbutene-1,5-methylpentene-1 and 6-methylbeptene-1; and mixturesthereof.

More complex polymer substrates, often designated as interpolymers, maybe prepared using a third component. The third component generally usedto prepare an interpolymer substrate is a polyene monomer selected fromnon-conjugated dienes and trienes. The non-conjugated diene component isone having from 5 to 14 carbon atoms in the chain. Preferably, the dienemonomer is characterized by the presence of a vinyl group in itsstructure and can include cyclic and bicyclo compounds. Representativedienes include 1,4-hexadiene, 1,4-cyclohexadiene, dicyclopentadiene,5-ethylidene-2-norbornene, 5-methylene-2-norborene, 1,5-heptadiene, and1,6-octadiene. A mixture of more than one diene can be used in thepreparation of the interpolymer. A preferred non-conjugated diene forpreparing a terpolymer or interpolymer substrate is 1,4-hexadiene.

The triene component will have at least two non-conjugated double bonds,and up to about 30 carbon atoms in the chain. Typical trienes useful inpreparing the interpolymer of this disclosure are1-isopropylidene-3a,4,7,7a-tetrahydroindene, 1-isopropylidenedicyclopentadiene, dihydro-isodicyclopentadiene, and2-(2-methylene-4-methyl-3-pentenyl) [2.2.1] bicyclo-5-heptene.

Ethylene-propylene or higher alpha-olefin copolymers may consist of fromabout 15 to 80 mole percent ethylene and from about 85 to 20 molepercent C₃ to C₁₈ alpha-olefin with the preferred mole ratios being fromabout 35 to 75 mole percent ethylene and from about 65 to 25 molepercent of a C₃ to C₁₈ alpha-olefin, with the more preferred proportionsbeing from 50 to 70 mole percent ethylene and 50 to 30 mole percent C₃to C₁₈ alpha-olefin, and the most preferred proportions being from 55 to65 mole percent ethylene and 45 to 35 mole percent C₃ to C₁₈alpha-olefin.

Terpolymer variations of the foregoing polymers may contain from about0.1 to 10 mole percent of a non-conjugated diene or triene.

The terms polymer and copolymer are used generically to encompassethylene copolymers, terpolymers or interpolymers. These materials maycontain minor amounts of other olefinic monomers so long as the basiccharacteristics of the ethylene copolymers are not materially changed.

The polymerization reaction used to form the ethylene-olefin copolymersubstrate may be generally carried out in the presence of a conventionalZiegler-Natta or metallocene catalyst system. The polymerization mediumis not specific and can include solution, slurry, or gas phaseprocesses, as known to those skilled in the aft. When solutionpolymerization is employed, the solvent may be any suitable inerthydrocarbon solvent that is liquid under reaction conditions forpolymerization of alpha-olefins; examples of satisfactory hydrocarbonsolvents include straight chain paraffins having from 5 to 8 carbonatoms, with hexane being preferred. Aromatic hydrocarbons, preferablyaromatic hydrocarbon having a single benzene nucleus, such as benzene,toluene and the like; and saturated cyclic hydrocarbons having boilingpoint ranges approximating those of the straight chain paraffinichydrocarbons and aromatic hydrocarbons described above, are particularlysuitable. The solvent selected may be a mixture of one or more of theforegoing hydrocarbons. When slurry polymerization is employed, theliquid phase for polymerization is preferably liquid propylene. It isdesirable that the polymerization medium be free of substances that willinterfere with the catalyst components.

In one embodiment, the olefin copolymer substrate is an ethylenecopolymer or terpolymer such as an oil soluble linear or branchedpolymer having a number average molecular weight of about 500 to about100,000, for example about 500 to about 40,000, about 500 to about10,000, about 500 to about 5,000, about 500 to about 3,000, or about1,000 to about 40,000, about 1,000 to about 20,000, about 5,000 to about20,000, about 1,000 to about 30,000, about 1,000 to about 10,000, orabout 1,000 to about 6,000.

The acyl groups grafted on to the olefin copolymer are obtained fromethylenically unsaturated carboxylic acid or anhydride reactants thatinclude at least one carbon-carbon double bond and further comprise atleast one carboxylic acid and/or dicarboxylic anhydride group. In oneapproach, the reactants forming the acyl groups grafted on to the olefincopolymer are selected acrylic acid, methacrylic acid, cinnamic acid,ferulic acid, ortho coumaric acid, meta coumaric acid, para coumaricacid, crotonic acid, maleic acid, maleic anhydride, fumaric acid,itaconic acid and itaconic anhydride or a combination thereof. Inanother approach, the reactants forming the acyl groups grafted on tothe olefin copolymer are selected from maleic acid, fumaric acid, maleicanhydride, or a combination thereof. In yet a further approach, thereactants forming the acyl groups grafted on to the olefin copolymerinclude maleic anhydride moieties.

In one embodiment, the olefin copolymer has grafted thereon from about0.1 to about 0.8 acyl groups per 1000 number average molecular weightunits of olefin copolymer, for example about 0.2 to about 0.75, about0.2 to about 0.5, about 0.3 to about 0.5, or about 0.4 to about 0.5, orabout 0.1 to about 0.5. In some further embodiments, the olefincopolymer has grafted thereon about 0.2, about 0.3, about 0.4, about0.5, about 0.6, or about 0.75 acyl groups per 1000 number averagemolecular weight units of olefin copolymer or any range in between suchend points.

The carboxylic reactant is grafted onto the prescribed polymer backbonein an amount to provide about 0.1 to about 0.8 acyl groups per 1000number average molecular weight units of the polymer backbone,preferably about 0.2 to about 0.5 acyl groups per 1000 number averagemolecular weight (or other amounts described in the previous paragraph).For example, and in one approach, a copolymer substrate with Mn of20,000 is grafted with 6 to 15 carboxylic groups per polymer chain or 3to 7.5 moles of maleic anhydride per mole of polymer. A copolymer withMn of 100,000 is grafted with 30 to 75 carboxylic groups per polymerchain or 15 to 37.5 moles of maleic anhydride per polymer chain. Theminimum level of functionality is the level needed to achieve theminimum satisfactory dispersancy performance. Above the maximumfunctionality level little, if any, additional dispersancy performanceis noted and other properties of the additive may be adversely affected.

The grafting reaction to form the acylated olefin copolymers isgenerally carried out with the aid of a free-radical initiator either insolution or in bulk, as in an extruder or intensive mixing device. Whenthe polymerization is carried out in hexane solution, it is economicallyconvenient to carry out the grafting reaction in hexane as described inU.S. Pat. Nos. 4,340,689; 4,670,515 and 4,948,842 incorporated herein byreference. The resulting polymer intermediate is characterized by havingcarboxylic acid acylating functionality randomly within its structure.

In the bulk process for forming the acylated olefin copolymers, theolefin copolymer is fed to rubber or plastic processing equipment suchas an extruder, intensive mixer or masticator, heated to a temperatureof 150° to 400° C. and the ethylenically unsaturated carboxylic acidreagent and free-radical initiator are separately co-fed to the moltenpolymer to effect grafting. The reaction is carried out optionally withmixing conditions to effect shearing and grafting of the ethylenecopolymers according to U.S. Pat. No. 5,075,383, incorporated herein byreference. The processing equipment is generally purged with nitrogen toprevent oxidation of the polymer and to aid in venting unreactedreagents and byproducts of the grafting reaction. The residence time inthe processing equipment is sufficient to provide for the desired degreeof acylation and to allow for purification of the acylated copolymer viaventing. Mineral or synthetic lubricating oil may optionally be added tothe processing equipment after the venting stage to dissolve theacylated copolymer.

The free-radical initiators which may be used to graft the ethylenicallyunsaturated carboxylic acid material to the polymer backbone includeperoxides, hydroperoxides, peresters, and also azo compounds andpreferably those which have a boiling point greater than 100° C. anddecompose thermally within the grafting temperature range to providefree radicals. Representatives of these free-radical initiators areazobutyronitrile, dicumyl peroxide,2,5-dimethylhexane-2,5-bis-tertiarybutyl peroxide and2,5-dimnethylhex-3-yne-2,5-bis-tertiary-butyl peroxide. The initiator isused in an amount of between about 0.005% and about 1% by weight basedon the weight of the reaction mixture.

Other methods known in the art for effecting reaction of ethylene-olefincopolymers with ethylenically unsaturated carboxylic reagents, such ashalogenation reactions, thermal or “ene” reactions or mixtures thereof,can be used instead of the free-radical grafting process. Such reactionsare conveniently carried out in mineral oil or bulk by heating thereactants at temperatures of about 250° to about 400° C. under an inertatmosphere to avoid the generation of free radicals and oxidationbyproducts. “Ene” reactions are a preferred method of grafting when theethylene-olefin copolymer contains unsaturation. To achieve the highgraft levels, 0.1 to 0.8 acyl groups per 1000 Mn, desired by thisdisclosure, it may be necessary to follow or proceed the “ene” orthermal graft reaction with a free radical graft reaction.

Definitions

As used herein, the term “effective concentration” refers to theconcentration of the viscosity modifier necessary for a sooted base oilto show Newtonian behavior, which indicates that the soot particles inthe base oil are sufficiently dispersed.

As used herein, the term “olefin copolymer” refers to a polymercomprised of two or more different types of monomers, wherein allmonomers contain at least one olefin (carbon-carbon double bond).

A major amount of a compound generally refers to greater than about 50weight percent.

For purposes of this disclosure, the chemical elements are identified inaccordance with the Periodic Table of the Elements, CAS version,Handbook of Chemistry and Physics, 75th Ed. Additionally, generalprinciples of organic chemistry are described in “Organic Chemistry”,Thomas Sorrell, University Science Books, Sausolito: 1999, and “March'sAdvanced Organic Chemistry”, 5th Ed., Ed.: Smith, M. B. and March, J.,John Wiley & Sons, New York: 2001, the entire contents of which arehereby incorporated by reference.

As described herein, compounds may optionally be substituted with one ormore substituents, such as are illustrated generally above, or asexemplified by particular classes, subclasses, and species of thedisclosure.

As used herein the term “aliphatic” encompasses the terms alkyl,alkenyl, alkynyl, each of which being optionally substituted as setforth below.

As used herein, an “alkyl” group refers to a saturated aliphatichydrocarbon group containing 1-12 (e.g., 1-8, 1-6, or 1-4) carbon atoms.An alkyl group can be straight or branched. Examples of alkyl groupsinclude, but are not limited to, methyl, ethyl, propyl, isopropyl,butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-heptyl, or2-ethylhexyl. An alkyl group can be substituted (i.e., optionallysubstituted) with one or more substituents such as halo, phospho,cycloaliphatic [e.g., cycloalkyl or cycloalkenyl], heterocycloaliphatic[e.g., heterocycloalkyl or heterocycloalkenyl], aryl, heteroaryl,alkoxy, aroyl, heteroaroyl, acyl [e.g., (aliphatic)carbonyl,(cycloaliphatic)carbonyl, or (heterocycloaliphatic)carbonyl], nitro,cyano, amido [e.g., (cycloalkylalkyl)carbonylamino, arylcarbonylamino,aralkylcarbonylamino, (heterocycloalkyl)carbonylamino,(heterocycloalkylalkyl) carbonylamino, heteroarylcarbonylamino,heteroaralkylcarbonylamino alkylaminocarbonyl, cycloalkylaminocarbonyl,heterocycloalkylaminocarbonyl, arylaminocarbonyl, orheteroarylaminocarbonyl], amino [e.g., aliphaticamino,cycloaliphaticamino, or heterocycloaliphaticamino], sulfonyl [e.g.,aliphatic-SO₂—], sulfinyl, sulfanyl, sulfoxy, urea, thiourea, sulfamoyl,sulfamide, oxo, carboxy, carbamoyl, cycloaliphaticoxy,heterocycloaliphaticoxy, aryloxy, heteroaryloxy, aralkyloxy,heteroarylalkoxy, alkoxycarbonyl, alkylcarbonyloxy, or hydroxy. Withoutlimitation, some examples of substituted alkyls include carboxyalkyl(such as HOOC-alkyl, alkoxycarbonylalkyl, and alkylcarbonyloxyalkyl),cyanoalkyl, hydroxyalkyl, alkoxyalkyl, acylalkyl, aralkyl,(alkoxyaryl)alkyl, (sulfonylamino)alkyl (such as(alkyl-SO₂-amino)alkyl), aminoalkyl, amidoalkyl, (cycloaliphatic)alkyl,or haloalkyl.

As used herein, an “alkenyl” group refers to an aliphatic carbon groupthat contains 2-8 (e.g., 2-12, 2-6, or 2-4) carbon atoms and at leastone double bond. Like an alkyl group, an alkenyl group can be straightor branched. Examples of an alkenyl group include, but are not limitedto allyl, isoprenyl, 2-butenyl, and 2-hexenyl. An alkenyl group can beoptionally substituted with one or more substituents such as halo,phospho, cycloaliphatic [e.g., cycloalkyl or cycloalkenyl],heterocycloaliphatic [e.g., heterocycloalkyl or hetero cycloalkenyl],aryl, heteroaryl, alkoxy, aroyl, heteroaroyl, acyl [e.g., (aliphatic)carbonyl, (cycloaliphatic)carbonyl, or (heterocycloaliphatic)carbonyl],nitro, cyano, amido [e.g., (cycloalkylalkyl)carbonylamino,arylcarbonylamino, aralkylcarbonylamino, (hetero cycloalkyl)carbonylamino, (heterocycloalkylalkyl)carbonylamino,heteroarylcarbonylamino, heteroaralkylcarbonylamino alkylaminocarbonyl,cycloalkylaminocarbonyl, hetero cyclo alkylaminocarbonyl, arylaminocarbonyl, or heteroarylaminocarbonyl], amino [e.g., aliphaticamino,cycloaliphaticamino, heterocycloaliphaticamino, oraliphaticsulfonylamino]sulfonyl [e.g., alkyl-SO₂—, cycloaliphatic-SO₂—,or aryl-SO₂—], sulfinyl, sulfanyl, sulfoxy, urea, thiourea, sulfamoyl,sulfamide, oxo, carboxy, carbamoyl, cycloaliphaticoxy,heterocycloaliphaticoxy, aryloxy, heteroaryloxy, aralkyloxy,heteroaralkoxy, alkoxycarbonyl, alkylcarbonyloxy, or hydroxy. Withoutlimitation, some examples of substituted alkenyls include cyanoalkenyl,alkoxyalkenyl, acylalkenyl, hydroxyalkenyl, aralkenyl,(alkoxyaryl)alkenyl, (sulfonylamino)alkenyl (such as(alkyl-SO₂-amino)alkenyl), aminoalkenyl, amidoalkenyl,(cycloaliphatic)alkenyl, or haloalkenyl.

As used herein, an “alkynyl” group refers to an aliphatic carbon groupthat contains 2-8 (e.g., 2-12, 2-6, or 2-4) carbon atoms and has atleast one triple bond. An alkynyl group can be straight or branched.Examples of an alkynyl group include, but are not limited to, propargyland butynyl. An alkynyl group can be optionally substituted with one ormore substituents such as aroyl, heteroaroyl, alkoxy, cycloalkyloxy,heterocycloalkyloxy, aryloxy, heteroaryloxy, aralkyloxy, nitro, carboxy,cyano, halo, hydroxy, sulfo, mercapto, sulfanyl [e.g., aliphaticsulfanylor cycloaliphaticsulfanyl], sulfinyl [e.g., aliphaticsulfinyl orcycloaliphaticsulfinyl], sulfonyl [e.g., aliphatic-SO₂—,aliphaticamino-SO₂—, or cycloaliphatic-SO₂—], amido [e.g.,aminocarbonyl, alkylaminocarbonyl, alkylcarbonylamino, cycloalkylaminocarbonyl, heterocycloalkylaminocarbonyl,cycloalkylcarbonylamino, arylamino carbonyl, arylcarbonylamino,aralkylcarbonylamino, (heterocycloalkyl) carbonylamino,(cycloalkylalkyl)carbonylamino, heteroaralkylcarbonylamino, heteroarylcarbonylamino or heteroarylaminocarbonyl], urea, thiourea, sulfamoyl,sulfamide, alkoxycarbonyl, alkyl carbonyloxy, cycloaliphatic,heterocycloaliphatic, aryl, heteroaryl, acyl [e.g., (cycloaliphatic)carbonyl or (heterocycloaliphatic)carbonyl], amino [e.g.,aliphaticamino], sulfoxy, oxo, carboxy, carbamoyl, (cycloaliphatic)oxy,(heterocyclo aliphatic) oxy, or (heteroaryl)alkoxy.

As used herein, an “amino” group refers to —NR^(X)R^(Y) wherein each ofR^(X) and R^(Y) is independently hydrogen, alkyl, cycloakyl,(cycloalkyl)alkyl, aryl, aralkyl, heterocycloalkyl,(heterocycloalkyl)alkyl, heteroaryl, carboxy, sulfanyl, sulfinyl,sulfonyl, (alkyl)carbonyl, (cycloalkyl)carbonyl,((cycloalkyl)alkyl)carbonyl, arylcarbonyl, (aralkyl)carbonyl,(heterocycloalkyl)carbonyl, ((heterocycloalkyl)alkyl)carbonyl,(heteroaryl)carbonyl, or (heteroaralkyl)carbonyl, each of which beingdefined herein and being optionally substituted. Examples of aminogroups include alkylamino, dialkylamino, or arylamino. When the term“amino” is not the terminal group (e.g., alkylcarbonylamino), it isrepresented by —NR^(X)—R^(X) has the same meaning as defined above.

As used herein, a “cycloalkyl” group refers to a saturated carbocyclicmono- or bicyclic (fused or bridged) ring of 3-10 (e.g., 5-10) carbonatoms. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cycloheptyl, adamantyl, norbornyl, cubyl,octahydro-indenyl, decahydro-naphthyl, bicyclo[3.2.1]octyl,bicyclo[2.2.2] octyl, bicyclo[3.3.1]nonyl, bicyclo[3.3.2]decyl,bicyclo[2.2.2]octyl, adamantyl, or((aminocarbonyl)cycloalkyl)cycloalkyl.

As used herein, a “heterocycloalkyl” group refers to a 3-10 memberedmono- or bicylic (fused or bridged) (e.g., 5- to 10-membered mono- orbicyclic) saturated ring structure, in which one or more of the ringatoms is a heteroatom (e.g., N, O, S, or combinations thereof). Examplesof a heterocycloalkyl group include piperidyl, piperazyl,tetrahydropyranyl, tetrahydrofuryl, 1,4-dioxolanyl, 1,4-dithianyl,1,3-dioxolanyl, oxazolidyl, isoxazolidyl, morpholinyl, thiomorpholyl,octahydrobenzofuryl, octahydrochromenyl, octahydrothiochromenyl,octahydroindolyl, octahydropyrindinyl, decahydroquinolinyl,octahydrobenzo[b]thiopheneyl, 2-oxa-bicyclo[2.2.2]octyl,1-aza-bicyclo[2.2.2]octyl, 3-aza-bicyclo[3.2.1]octyl, and2,6-dioxa-tricyclo[3.3.1.0]nonyl. A monocyclic heterocycloalkyl groupcan be fused with a phenyl moiety to form structures, such astetrahydroisoquinoline, which would be categorized as heteroaryls.

A “heteroaryl” group, as used herein, refers to a monocyclic, bicyclic,or tricyclic ring system having 4 to 15 ring atoms wherein one or moreof the ring atoms is a heteroatom (e.g., N, O, S, or combinationsthereof) and in which the monocyclic ring system is aromatic or at leastone of the rings in the bicyclic or tricyclic ring systems is aromatic.A heteroaryl group includes a benzofused ring system having 2 to 3rings. For example, a benzofused group includes benzo fused with one ortwo 4 to 8 membered heterocycloaliphatic moieties (e.g., indolizyl,indolyl, isoindolyl, 3H-indolyl, indolinyl, benzo[b]furyl,benzo[b]thiophenyl, quinolinyl, or isoquinolinyl). Some examples ofheteroaryl are azetidinyl, pyridyl, 1H-indazolyl, furyl, pyrrolyl,thienyl, thiazolyl, oxazolyl, imidazolyl, tetrazolyl, benzofuryl,isoquinolinyl, benzthiazolyl, xanthene, thioxanthene, phenothiazine,dihydroindole, benzo[1,3]dioxole, benzo[b]furyl, benzo[b]thiophenyl,indazolyl, benzimidazolyl, benzthiazolyl, puryl, cinnolyl, quinolyl,quinazolyl, cinnolyl, phthalazyl, quinazolyl, quinoxalyl, isoquinolyl,4H-quinolizyl, benzo-1,2,5-thiadiazolyl, or 1,8-naphthyridyl.

Without limitation, monocyclic heteroaryls include furyl, thiophenyl,2H-pyrrolyl, pyrrolyl, oxazolyl, thazolyl, imidazolyl, pyrazolyl,isoxazolyl, isothiazolyl, 1,3,4-thiadiazolyl, 2H-pyranyl, 4-H-pranyl,pyridyl, pyridazyl, pyrimidyl, pyrazolyl, pyrazyl, or 1,3,5-triazyl.Monocyclic heteroaryls are numbered according to standard chemicalnomenclature.

Without limitation, bicyclic heteroaryls include indolizyl, indolyl,isoindolyl, 3H-indolyl, indolinyl, benzo[b]furyl, benzo[b]thiophenyl,quinolinyl, isoquinolinyl, indolizinyl, isoindolyl, indolyl,benzo[b]furyl, bexo[b]thiophenyl, indazolyl, benzimidazyl,benzthiazolyl, purinyl, 4H-quinolizyl, quinolyl, isoquinolyl, cinnolyl,phthalazyl, quinazolyl, quinoxalyl, 1,8-naphthyridyl, or pteridyl.Bicyclic heteroaryls are numbered according to standard chemicalnomenclature.

A hydrocarbyl group refers to a group that has a carbon atom directlyattached to a remainder of the molecule and each hydrocarbyl group isindependently selected from hydrocarbon substituents, and substitutedhydrocarbon substituents may contain one or more of halo groups,hydroxyl groups, alkoxy groups, mercapto groups, nitro groups, nitrosogroups, amino groups, sulfoxy groups, pyridyl groups, furyl groups,thienyl groups, imidazolyl groups, sulfur, oxygen and nitrogen, andwherein no more than two non-hydrocarbon substituents are present forevery ten carbon atoms in the hydrocarbyl group.

The novel dispersant viscosity index modifiers described herein can beused as part of a lubricating oil composition or provided as an additiveconcentrate. Accordingly, the lubricating oil compositions orconcentrate may further comprise a base oil as described below. In oneapproach, a lubricant oil composition may include about 0.1 to about 10weight percent of the capped polymer (not including any diluent oil thatmay be included with the polymer). In other approaches, the highlygrafted multi-functional olefin copolymer viscosity modifier is providedas an additive concentrate in diluent or base oil. The additiveconcentrate may include about 10 to about 60 weight percent viscositymodifier polymer in diluent or base oil.

Base Oil

The dispersant viscosity index modifiers of the present disclosure maybe blended with a majority of base oil in either a lubricant or additiveconcentrate. Base oils suitable for use in formulating engine lubricantcompositions and/or the metal working compositions (or other lubricatingcomposition) and/or additive concentrates may be selected from any ofsuitable synthetic oils, animal oils, vegetable oils, mineral oils ormixtures thereof. Animal oils and vegetable oils (e.g., lard oil, castoroil) as well as mineral lubricating oils such as liquid petroleum oilsand solvent treated or acid-treated mineral lubricating oils of theparaffinic, naphthenic or mixed paraffinic-naphthenic types may be used.Oils derived from coal or shale may also be suitable. The base oiltypically may have a viscosity of about 2 to about 15 cSt or, as afurther example, about 2 to about 10 cSt at 100° C. Further, an oilderived from a gas-to-liquid process is also suitable.

Suitable synthetic base oils may include alkyl esters of dicarboxylicacids, polyglycols and alcohols, poly-alpha-olefins, includingpolybutenes, alkyl benzenes, organic esters of phosphoric acids, andpolysilicone oils. Synthetic oils include hydrocarbon oils such aspolymerized and interpolymerized olefins (e.g., polybutylenes,polypropylenes, propylene isobutylene copolymers, etc.);poly(1-hexenes), poly-(1-octenes), poly(1-decenes), etc. and mixturesthereof; alkylbenzenes (e.g., dodecylbenzenes, tetradecylbenzenes,di-nonylbenzenes, di-(2-ethylhexyl)benzenes, etc.); polyphenyls (e.g.,biphenyls, terphenyl, alkylated polyphenyls, etc.); alkylated diphenylethers and alkylated diphenyl sulfides and the derivatives, analogs andhomologs thereof and the like.

Alkylene oxide polymers and interpolymers and derivatives thereof wherethe terminal hydroxyl groups have been modified by esterification,etherification, etc., constitute another class of known synthetic oilsthat may be used. Such oils are exemplified by the oils prepared throughpolymerization of ethylene oxide or propylene oxide, the alkyl and arylethers of these polyoxyalkylene polymers (e.g., methyl-polyisopropyleneglycol ether having an average molecular weight of about 1000, diphenylether of polyethylene glycol having a molecular weight of about500-1000, diethyl ether of polypropylene glycol having a molecularweight of about 1000-1500, etc.) or mono- and polycarboxylic estersthereof, for example, the acetic acid esters, mixed C₃-C₈ fatty acidesters, or the C₁₃ oxo-acid diester of tetraethylene glycol.

Another class of synthetic oils that may be used includes the esters ofdicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinicacids, alkenyl succinic acids, maleic acid, azelaic acid, suberic acid,sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonicacid, alkyl malonic acids, alkenyl malonic acids, etc.) with a varietyof alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol,2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether,propylene glycol, etc.) Specific examples of these esters includedibutyl adipate, di(2-ethylhexyl)sebacate, di-n-hexyl fumarate, dioctylsebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate,didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester oflinoleic acid dimer, the complex ester formed by reacting one mole ofsebacic acid with two moles of tetraethylene glycol and two moles of2-ethylhexanoic acid and the like.

Esters useful as synthetic oils also include those made from C₅ to C₁₂monocarboxylic acids and polyols and polyol ethers such as neopentylglycol, trimethylol propane, pentaerythritol, dipentaerythritol,tripentaerythritol, etc.

Hence, the base oil used which may be used to make the engine and/ormetalworking lubricant compositions as described herein may be selectedfrom any of the base oils in Groups I-V as specified in the AmericanPetroleum Institute (API) Base Oil Interchangeability Guidelines. Suchbase oil groups are as follows:

TABLE 1 Base Oil Sulfur Saturates Viscosity Group¹ (wt %) (wt. %) IndexGroup I >0.03 And/or <90 80 to 120 Group II ≤0.03 And ≥90 80 to 120Group III ≤0.03 And ≥90 ≥120 Group IV all polyalphaolefins (PAOs) GroupV all others not included in Groups I-IV ¹Groups I-III are mineral oilbase stocks.

The base oil may contain a minor or major amount of a poly-alpha-olefin(PAO). Typically, the poly-alpha-olefins are derived from monomershaving from about 4 to about 30, or from about 4 to about 20, or fromabout 6 to about 16 carbon atoms. Examples of useful PAOs include thosederived from octene, decene, mixtures thereof, and the like. PAOs mayhave a viscosity of from about 2 to about 15, or from about 3 to about12, or from about 4 to about 8 cSt at 100° C. Examples of PAOs include 4cSt at 100° C. poly-alpha-olefins, 6 cSt at 100° C. poly-alpha-olefins,and mixtures thereof. Mixtures of mineral oil with the foregoingpoly-alpha-olefins may be used.

The base oil may be an oil derived from Fischer-Tropsch synthesizedhydrocarbons. Fischer-Tropsch synthesized hydrocarbons are made fromsynthesis gas containing H₂ and CO using a Fischer-Tropsch catalyst.Such hydrocarbons typically require further processing in order to beuseful as the base oil. For example, the hydrocarbons may behydroisomerized using processes disclosed in U.S. Pat. No. 6,103,099 or6,180,575; hydrocracked and hydroisomerized using processes disclosed inU.S. Pat. No. 4,943,672 or 6,096,940; dewaxed using processes disclosedin U.S. Pat. No. 5,882,505; or hydroisomerized and dewaxed usingprocesses disclosed in U.S. Pat. Nos. 6,013,171; 6,080,301; or6,165,949.

Unrefined, refined, and rerefined oils, either natural or synthetic (aswell as mixtures of two or more of any of these) of the type disclosedhereinabove can be used in the base oils. Unrefined oils are thoseobtained directly from a natural or synthetic source without furtherpurification treatment. For example, a shale oil obtained directly fromretorting operations, a petroleum oil obtained directly from primarydistillation or ester oil obtained directly from an esterificationprocess and used without further treatment would be an unrefined oil.Refined oils are similar to the unrefined oils except they have beenfurther treated in one or more purification steps to improve one or moreproperties. Many such purification techniques are known to those skilledin the art such as solvent extraction, secondary distillation, acid orbase extraction, filtration, percolation, etc. Rerefined oils areobtained by processes similar to those used to obtain refined oilsapplied to refined oils which have been already used in service. Suchrerefined oils are also known as reclaimed or reprocessed oils and oftenare additionally processed by techniques directed to removal of spentadditives, contaminants, and oil breakdown products.

The base oil may be combined with the emulsifying agent described hereinalong with optional additives to provide an engine lubricantcomposition. Accordingly, the base oil may be present in the enginelubricant composition in a major amount ranging from about 50 wt. % toabout 95 wt. % based on a total weight of the lubricant composition.

Other optional additives of the lubricating oils are described below.

Metal-containing Detergents

Metal detergents that may be used with the dispersant reaction productdescribed above generally comprise a polar head with a long hydrophobictail where the polar head comprises a metal salt of an acidic organiccompound. The salts may contain a substantially stoichiometric amount ofthe metal, in which case they are usually described as normal or neutralsalts, and would typically have a total base number or TBN (as measuredby ASTM D2896) of from about 0 to less than about 150. Large amounts ofa metal base may be included by reacting an excess of a metal compoundsuch as an oxide or hydroxide with an acidic gas such as carbon dioxide.The resulting overbased detergent comprises micelles of neutralizeddetergent surrounding a core of inorganic metal base (e.g., hydratedcarbonates). Such overbased detergents may have a TBN of about 150 orgreater, such as from about 150 to about 450 or more.

Detergents that may be suitable for use in the present embodimentsinclude oil-soluble overbased, low base, and neutral sulfonates,phenates, sulfurized phenates, and salicylates of a metal, particularlythe alkali or alkaline earth metals, e.g., sodium, potassium, lithium,calcium, and magnesium. More than one metal may be present, for example,both calcium and magnesium. Mixtures of calcium and/or magnesium withsodium may also be suitable. Suitable metal detergents may be overbasedcalcium or magnesium sulfonates having a TBN of from 150 to 450 TBN,overbased calcium or magnesium phenates or sulfurized phenates having aTBN of from 150 to 300 TBN, and overbased calcium or magnesiumsalicylates having a TBN of from 130 to 350. Mixtures of such salts mayalso be used.

The metal-containing detergent may be present in a lubricatingcomposition in an amount of from about 0.5 wt % to about 5 wt %. As afurther example, the metal-containing detergent may be present in anamount of from about 1.0 wt % to about 3.0 wt %. The metal-containingdetergent may be present in a lubricating composition in an amountsufficient to provide from about 500 to about 5000 ppm alkali and/oralkaline earth metal to the lubricant composition based on a totalweight of the lubricant composition. As a further example, themetal-containing detergent may be present in a lubricating compositionin an amount sufficient to provide from about 1000 to about 3000 ppmalkali and/or alkaline earth metal.

Phosphorus-based Anti-wear Agents

Phosphorus-based wear preventative agents may be used and may comprise ametal dihydrocarbyl dithiophosphate compound, such as but not limited toa zinc dihydrocarbyl dithiophosphate compound. Suitable metaldihydrocarbyl dithiophosphates may comprise dihydrocarbyldithiophosphate metal salts wherein the metal may be an alkali oralkaline earth metal, or aluminum, lead, tin, molybdenum, manganese,nickel, copper, or zinc.

Dihydrocarbyl dithiophosphate metal salts may be prepared in accordancewith known techniques by first forming a dihydrocarbyl dithiophosphoricacid (DDPA), usually by reaction of one or more alcohol or a phenol withP₂S₅ and then neutralizing the formed DDPA with a metal compound. Forexample, a dithiophosphoric acid may be made by reacting mixtures ofprimary and secondary alcohols. Alternatively, multiple dithiophosphoricacids can be prepared where the hydrocarbyl groups on one are entirelysecondary in character and the hydrocarbyl groups on the others areentirely primary in character. To make the metal salt, any basic orneutral metal compound could be used but the oxides, hydroxides andcarbonates are most generally employed. Commercial additives frequentlycontain an excess of metal due to the use of an excess of the basicmetal compound in the neutralization reaction.

The zinc dihydrocarbyl dithiophosphates (ZDDP) are oil soluble salts ofdihydrocarbyl dithiophosphoric acids and may be represented by thefollowing formula:

wherein R and R′ may be the same or different hydrocarbyl radicalscontaining from 1 to 18, for example 2 to 12, carbon atoms and includingradicals such as alkyl, alkenyl, aryl, arylalkyl, alkaryl, andcycloaliphatic radicals. R and R′ groups may be alkyl groups of 2 to 8carbon atoms. Thus, the radicals may, for example, be ethyl, n-propyl,i-propyl, n-butyl, butyl, sec-butyl, amyl, n-hexyl, i-hexyl, n-octyl,decyl, dodecyl, octadecyl, 2-ethylhexyl, phenyl, butylphenyl,cyclohexyl, methylcyclopentyl, propenyl, butenyl. In order to obtain oilsolubility, the total number of carbon atoms (i.e., R and R′) in thedithiophosphoric acid will generally be about 5 or greater. The zincdihydrocarbyl dithiophosphate can therefore comprise zinc dialkyldithiophosphates.

Other suitable components that may be utilized as the phosphorus-basedwear preventative include any suitable organophosphorus compound, suchas but not limited to, phosphates, thiophosphates, di-thiophosphates,phosphites, and salts thereof and phosphonates. Suitable examples aretricresyl phosphate (TCP), di-alkyl phosphite (e.g., dibutyl hydrogenphosphite), and amyl acid phosphate.

Another suitable component is a phosphorylated succinimide such as acompleted reaction product from a reaction between a hydrocarbylsubstituted succinic acylating agent and a polyamine combined with aphosphorus source, such as inorganic or organic phosphorus acid orester. Further, it may comprise compounds wherein the product may haveamide, amidine, and/or salt linkages in addition to the imide linkage ofthe type that results from the reaction of a primary amino group and ananhydride moiety.

The phosphorus-based wear preventative may be present in a lubricatingcomposition in an amount sufficient to provide from about 200 to about2000 ppm phosphorus. As a further example, the phosphorus-based wearpreventative may be present in a lubricating composition in an amountsufficient to provide from about 500 to about 800 ppm phosphorus.

The phosphorus-based wear preventative may be present in a lubricatingcomposition in an amount sufficient to provide a ratio of alkali and/oralkaline earth metal content (ppm) based on the total amount of alkaliand/or alkaline earth metal in the lubricating composition to phosphoruscontent (ppm) based on the total amount of phosphorus in the lubricatingcomposition of from about 1.6 to about 3.0 (ppm/ppm).

Friction Modifiers

Embodiments of the present disclosure may include one or more frictionmodifiers. Suitable friction modifiers may comprise metal containing andmetal-free friction modifiers and may include, but are not limited to,imidazolines, amides, amines, succinimides, alkoxylated amines,alkoxylated ether amines, amine oxides, amidoamines, nitriles, betaines,quaternary amines, imines, amine salts, amino guanadine, alkanolamides,phosphonates, metal-containing compounds, glycerol esters, and the like.

Suitable friction modifiers may contain hydrocarbyl groups that areselected from straight chain, branched chain, or aromatic hydrocarbylgroups or admixtures thereof, and may be saturated or unsaturated. Thehydrocarbyl groups may be composed of carbon and hydrogen or heteroatoms such as sulfur or oxygen. The hydrocarbyl groups may range fromabout 12 to about 25 carbon atoms and may be saturated or unsaturated.

Aminic friction modifiers may include amides of polyamines. Suchcompounds can have hydrocarbyl groups that are linear, either saturatedor unsaturated, or a mixture thereof and may contain from about 12 toabout 25 carbon atoms.

Further examples of suitable friction modifiers include alkoxylatedamines and alkoxylated ether amines. Such compounds may have hydrocarbylgroups that are linear, either saturated, unsaturated, or a mixturethereof. They may contain from about 12 to about 25 carbon atoms.Examples include ethoxylated amines and ethoxylated ether amines.

The amines and amides may be used as such or in the form of an adduct orreaction product with a boron compound such as a boric oxide, boronhalide, metaborate, boric acid or a mono-, di- or tri-alkyl borate.Other suitable friction modifiers are described in U.S. Pat. No.6,300,291, herein incorporated by reference.

Other suitable friction modifiers may include an organic, ashless(metal-free), nitrogen-free organic friction modifier. Such frictionmodifiers may include esters formed by reacting carboxylic acids andanhydrides with alkanols. Other useful friction modifiers generallyinclude a polar terminal group (e.g. carboxyl or hydroxyl) covalentlybonded to an oleophilic hydrocarbon chain. Esters of carboxylic acidsand anhydrides with alkanols are described in U.S. Pat. No. 4,702,850.Another example of an organic ashless nitrogen-free friction modifier isknown generally as glycerol monooleate (GMO) which may contain mono- anddiesters of oleic acid. Other suitable friction modifiers are describedin U.S. Pat. No. 6,723,685, herein incorporated by reference. Theashless friction modifier may be present in the lubricant composition inan amount ranging from about 0.1 to about 0.4 percent by weight based ona total weight of the lubricant composition.

Suitable friction modifiers may also include one or more molybdenumcompounds. The molybdenum compound may be selected from the groupconsisting of molybdenum dithiocarbamates (MoDTC), molybdenumdithiophosphates, molybdenum dithiophosphinates, molybdenum xanthates,molybdenum thioxanthates, molybdenum sulfides, a trinuclearorgano-molybdenum compound, molybdenum/amine complexes, and mixturesthereof.

Additionally, the molybdenum compound may be an acidic molybdenumcompound. Included are molybdic acid, ammonium molybdate, sodiummolybdate, potassium molybdate, and other alkaline metal molybdates andother molybdenum salts, e.g., hydrogen sodium molybdate, MoOCl₄,MoO₂Br₂, Mo₂O₃Cl₆, molybdenum trioxide or similar acidic molybdenumcompounds. Alternatively, the compositions can be provided withmolybdenum by molybdenum/sulfur complexes of basic nitrogen compounds asdescribed, for example, in U.S. Pat. Nos. 4,263,152; 4,285,822;4,283,295; 4,272,387; 4,265,773; 4,261,843; 4,259,195 and 4,259,194; andWO 94/06897.

Suitable molybdenum dithiocarbamates may be represented by the formula:

where R₁, R₂, R₃, and R₄ each independently represent a hydrogen atom, aC₁ to C₂₀ alkyl group, a C₆ to C₂₀ cycloalkyl, aryl, alkylaryl, oraralkyl group, or a C₃ to C₂₀ hydrocarbyl group containing an ester,ether, alcohol, or carboxyl group; and X₁, X₂, Y₁, and Y₂ eachindependently represent a sulfur or oxygen atom.

Examples of suitable groups for each of R₁, R₂, R₃, and R₄ include2-ethylhexyl, nonylphenyl, methyl, ethyl, n-propyl, iso-propyl, n-butyl,t-butyl, n-hexyl, n-octyl, nonyl, decyl, dodecyl, tridecyl, lauryl,oleyl, linoleyl, cyclohexyl and phenylmethyl. R₁ to R₄ may each have C₆to C₁₈ alkyl groups. X₁ and X₂ may be the same, and Y₁ and Y₂ may be thesame. X₁ and X₂ may both comprise sulfur atoms, and Y₁ and Y₂ may bothcomprise oxygen atoms.

Further examples of molybdenum dithiocarbamates include C₆-C₁₈ dialkylor diaryldithiocarbamates, or alkyl-aryldithiocarbamates such asdibutyl-, diamyl-di-(2-ethylhexyl)-, dilauryl-, dioleyl-, anddicyclohexyl-dithiocarbamate.

Another class of suitable organo-molybdenum compounds are trinuclearmolybdenum compounds, such as those of the formula Mo₃S_(k)L_(n)Q_(z)and mixtures thereof, wherein L represents independently selectedligands having organo groups with a sufficient number of carbon atoms torender the compound soluble or dispersible in the oil, n is from 1 to 4,k varies from 4 through 7, Q is selected from the group of neutralelectron donating compounds such as water, amines, alcohols, phosphines,and ethers, and z ranges from 0 to 5 and includes non-stoichiometricvalues. At least 21 total carbon atoms may be present among all theligands' organo groups, such as at least 25, at least 30, or at least 35carbon atoms. Additional suitable molybdenum compounds are described inU.S. Pat. No. 6,723,685, herein incorporated by reference.

The molybdenum compound may be present in a fully formulated enginelubricant in an amount to provide about 5 ppm to 500 ppm by weightmolybdenum. As a further example, the molybdenum compound may be presentin an amount to provide about 50 to 300 ppm by weight molybdenum. Aparticularly suitable amount of molybdenum compound may be an amountsufficient to provide from about 60 to about 250 ppm by weightmolybdenum to the lubricant composition.

Anti-foam Agents

In some embodiments, a foam inhibitor may form another componentsuitable for use in the compositions. Foam inhibitors may be selectedfrom silicones, polyacrylates, and the like. The amount of antifoamagent in the engine lubricant formulations described herein may rangefrom about 0.001 wt % to about 0.1 wt % based on the total weight of theformulation. As a further example, antifoam agent may be present in anamount from about 0.004 wt. % to about 0.008 wt. %.

Oxidation Inhibitor Components

Oxidation inhibitors or antioxidants reduce the tendency of base stocksto deteriorate in service which deterioration can be evidenced by theproducts of oxidation such as sludge and varnish-like deposits thatdeposit on metal surfaces and by viscosity growth of the finishedlubricant. Such oxidation inhibitors include hindered phenols,sulfurized hindered phenols, alkaline earth metal salts ofalkylphenolthioesters having C₅ to C₁₂ alkyl side chains, sulfurizedalkylphenols, metal salts of either sulfurized or nonsulfurizedalkylphenols, for example calcium nonylphenol sulfide, ashless oilsoluble phenates and sulfurized phenates, phosphosulfurized orsulfurized hydrocarbons, phosphorus esters, metal thiocarbamates, andoil soluble copper compounds as described in U.S. Pat. No. 4,867,890.

Other antioxidants that may be used include sterically hindered phenolsand esters thereof, diarylamines, alkylated phenothiazines, sulfurizedcompounds, and ashless dialkyldithiocarbamates. Non-limiting examples ofsterically hindered phenols include, but are not limited to,2,6-di-tertiary butylphenol, 2,6 di-tertiary butyl methylphenol,4-ethyl-2,6-di-tertiary butylphenol, 4-propyl-2,6-di-tertiarybutylphenol, 4-butyl-2,6-di-tertiary butylphenol,4-pentyl-2,6-di-tertiary butylphenol, 4-hexyl-2,6-di-tertiarybutylphenol, 4-heptyl-2,6-di-tertiary butylphenol,4-(2-ethylhexyl)-2,6-di-tertiary butylphenol, 4-octyl-2,6-di-tertiarybutylphenol, 4-nonyl-2,6-di-tertiary butylphenol,4-decyl-2,6-di-tertiary butylphenol, 4-undecyl-2,6-di-tertiarybutylphenol, 4-dodecyl-2,6-di-tertiary butylphenol, methylene bridgedsterically hindered phenols including but not limited to4,4-methylenebis(6-tert-butyl-o-cresol),4,4-methylenebis(2-tert-amyl-o-cresol), 2,2-methylenebis(4-methyl-6tert-butylphenol, 4,4-methylene-bis(2,6-di-tert-butylphenol) andmixtures thereof as described in U.S Publication No. 2004/0266630.

Diarylamine antioxidants include, but are not limited to diarylamineshaving the formula:

wherein R′ and R″ each independently represents a substituted orunsubstituted aryl group having from 6 to 30 carbon atoms. Illustrativeof substituents for the aryl group include aliphatic hydrocarbon groupssuch as alkyl having from 1 to 30 carbon atoms, hydroxy groups, halogenradicals, carboxylic acid or ester groups, or nitro groups.

The aryl group is preferably substituted or unsubstituted phenyl ornaphthyl, particularly wherein one or both of the aryl groups aresubstituted with at least one alkyl having from 4 to 30 carbon atoms,preferably from 4 to 18 carbon atoms, most preferably from 4 to 9 carbonatoms. It is preferred that one or both aryl groups be substituted, e.g.mono-alkylated diphenylamine, di-alkylated diphenylamine, or mixtures ofmono- and di-alkylated diphenylamines.

The diarylamines may be of a structure containing more than one nitrogenatom in the molecule. Thus the diarylamine may contain at least twonitrogen atoms wherein at least one nitrogen atom has two aryl groupsattached thereto, e.g. as in the case of various diamines having asecondary nitrogen atom as well as two aryls on one of the nitrogenatoms.

Examples of diarylamines that may be used include, but are not limitedto: diphenylamine; various alkylated diphenylamines;3-hydroxydiphenylamine; N-phenyl-1,2-phenylenediamine;N-phenyl-1,4-phenylenediamine; monobutyldiphenyl-amine;dibutyldiphenylamine; monooctyldiphenylamine; dioctyldiphenylamine;monononyldiphenylamine; dinonyldiphenylamine;monotetradecyldiphenylamine; ditetradecyldiphenylamine,phenyl-alpha-naphthylamine; monooctyl phenyl-alpha-naphthylamine;phenyl-beta-naphthylamine; monoheptyldiphenylamine;diheptyl-diphenylamine; p-oriented styrenated diphenylamine; mixedbutyloctyldi-phenylamine; and mixed octylstyryldiphenylamine.

The sulfur containing antioxidants include, but are not limited to,sulfurized olefins that are characterized by the type of olefin used intheir production and the final sulfur content of the antioxidant. Highmolecular weight olefins, i.e. those olefins having an average molecularweight of 168 to 351 g/mol, are preferred. Examples of olefins that maybe used include alpha-olefins, isomerized alpha-olefins, branchedolefins, cyclic olefins, and combinations of these.

Alpha-olefins include, but are not limited to, any C₄ to C₂₅alpha-olefins. Alpha-olefins may be isomerized before the sulfurizationreaction or during the sulfurization reaction. Structural and/orconformational isomers of the alpha olefin that contain internal doublebonds and/or branching may also be used. For example, isobutylene is abranched olefin counterpart of the alpha-olefin 1-butene.

Sulfur sources that may be used in the sulfurization reaction of olefinsinclude: elemental sulfur, sulfur monochloride, sulfur dichloride,sodium sulfide, sodium polysulfide, and mixtures of these added togetheror at different stages of the sulfurization process.

Unsaturated oils, because of their unsaturation, may also be sulfurizedand used as an antioxidant. Examples of oils or fats that may be usedinclude corn oil, canola oil, cottonseed oil, grapeseed oil, olive oil,palm oil, peanut oil, coconut oil, rapeseed oil, safflower seed oil,sesame seed oil, soybean oil, sunflower seed oil, tallow, andcombinations of these.

The amount of sulfurized olefin or sulfurized fatty oil delivered to thefinished lubricant is based on the sulfur content of the sulfurizedolefin or fatty oil and the desired level of sulfur to be delivered tothe finished lubricant. For example, a sulfurized fatty oil or olefincontaining 20 wt. % sulfur, when added to the finished lubricant at a1.0 wt. % treat level, will deliver 2000 ppm of sulfur to the finishedlubricant. A sulfurized fatty oil or olefin containing 10 wt. % sulfur,when added to the finished lubricant at a 1.0 wt. % treat level, willdeliver 1000 ppm sulfur to the finished lubricant. It is desirable thatthe sulfurized olefin or sulfurized fatty oil to deliver between 200 ppmand 2000 ppm sulfur to the finished lubricant.

A suitable engine lubricant may include additive components in theranges listed in Table 2 with broad and narrower ranges, wherein baseoil makes up the balance of the lubricant.

TABLE 2 Component Wt. % Wt. % Novel dispersant viscosity index 0.1 to 100.1 to 5 modifier polymer* Additional Dispersants  0-10  1-6Antioxidants 0-5 0.01-3  Metal Detergents  0-15 0.1-8 CorrosionInhibitor 0-5  0-2 Metal dihydrocarbyl dithiophosphate 0-6 0.1-4Ash-free amine phosphate salt 0-6 0.0-4 Antifoaming agents 0-5 0.001-0.15 Antiwear agents 0-1    0-0.8 Pour point depressant 0-5 0.01-1.5 Viscosity modifier  0-20 0.25-10 Friction modifiers 0-2 0.1-1*polymer only (polymer may be provided as a concentrate as describedabove)

Additional optional additives that may be included in lubricantcompositions described herein include, but are not limited to, rustinhibitors, emulsifiers, demulsifiers, and oil-solubletitanium-containing additives.

Additives used in formulating the compositions described herein may beblended into the base oil individually or in various sub-combinations.However, it may be suitable to blend all of the components concurrentlyusing an additive concentrate (i.e., additives plus a diluent, such as ahydrocarbon solvent). The use of an additive concentrate may takeadvantage of the mutual compatibility afforded by the combination ofingredients when in the form of an additive concentrate. Also, the useof a concentrate may reduce blending time and may lessen the possibilityof blending errors.

The present disclosure provides novel lubricating oil blendsspecifically formulated for use as automotive engine lubricants.Embodiments of the present disclosure may provide lubricating oilssuitable for engine applications that provide improvements in one ormore of the following characteristics: antioxidancy, antiwearperformance, rust inhibition, fuel economy, water tolerance, airentrainment, seal protection, and foam reducing properties.

A better understanding of the present disclosure and its many advantagesmay be clarified with the following examples. The following examples areillustrative and not limiting thereof in either scope or spirit. Thoseskilled in the art will readily understand that variations of thecomponents, methods, steps, and devices described in these examples canbe used. Unless noted otherwise or apparent from the context ofdiscussion, all percentages, ratios, and parts noted in this disclosureare by weight.

EXAMPLES

Materials and Methods

The reactions described herein were performed in a 500 mL flask withoverhead stirring, a water removal condenser, temperature probe, andnitrogen supply. If needed, the reactions were heated using anisomantle.

In the general scheme above, an olefin copolymer is grafted with anacylating agent. The acyl grafting of the olefin polymer may beaccomplished with an appropriate technique known to those having skillin the art, such as using carbon radicals produced from an olefin bondusing a radical initiator, such as dicumyl peroxide. Other radicalinitiators are known to those having skill in the art. The grafted acidor anhydride can then undergo coupling chemistry (in the case of anacid) or a dehydration reaction (in the case of an anhydride) with acompound of Formula I, wherein X and ring A are defined herein. Theformation of ring A can be accomplished before or after coupling to theacid functionalized olefin copolymer. In Scheme 1, a coupling reactionof the polymer with the polyamine of Formula I is pictured, but in thecase of an anhydride or dicarboxylic acid, such as maleic anhydride, theprimary amine of the compound of Formula I would react with bothcarbonyl moieties of the anhydride to form an imide bond.

Example 1 Maleated Low Molecular Weight OCP Reacted with TEPA and Cappedwith Naphthalic Anhydride

An ethylene propylene copolymer (Mn=5400, 45.54 wt % of reaction mass),and maleic anhydride (Sigma Aldrich, 1.21 wt % of reaction mass) werecharged into a two-neck round-bottom flask equipped with a condenser anda Dean Stark apparatus under a nitrogen blanket. The flask was heated to165° C. and held for 1 hour to ensure good dissolution of the polymers.After complete dissolution, dicumyl peroxide (Sigma Aldrich, 0.19 wt %of reaction mass) was charged to the flask, held for 1 hour, andfollowed by another dicumyl peroxide addition (0.20 wt % of reactionmass). The resulting mixture was allowed to react for 1 hour. After thereaction was complete, the flask was heated to 230° C. under vacuum (25mm Hg) for 4 hours to remove unreacted maleic anhydride. A Group II baseoil (Phillip66 110N, 44.07 wt % of reaction mass) was added to the flaskand the reaction temperature was set to 165° C. A mixture oftetraethylenepentramine (Sigma Aldrich, TEPA, 1.21 wt % of reactionmass), optional Surfonic L24-2 (Huntsman, 7.00 wt % of reaction mass),and naphthalic anhydride (Sigma Aldrich, 0.57 wt % of reaction mass) wascharged to the flask at 165° C., and reacted for 4 hours to provide thefinal product, which had a kinematic viscosity at 100° C. of 176.8 cSt.For this Example, one mixture of the reactants was prepared.

The final product was tested and shown to have good soot handlingproperties. FIG. 1 shows that the product polymer has an effectiveconcentration in sooted oil of 1.5 wt %. In order to evaluate lubricantformulations according to this disclosure, the capped polymers hereinwere tested for their ability to disperse soot. Without dispersant, anoil containing soot particles has a shear thinning (non-Newtonian)behavior where viscosity decreases with increasing shear rate due to theagglomeration of soot particles at low shear rate resulting in highviscosity. On the other hand, at higher shear rate, soot particleagglomeration was broken up resulting in low viscosity. If dispersant isadded to a sooted oil, the soot particles are protected by dispersantwithout agglomeration, thus the oil has an ideally viscous or Newtonianfluid behavior where viscosity is independent of shear rate (See, e.g.,Thomas G. Mezger, The Rheology Handbook, 3^(rd) Revised Edition, 2011,which is incorporated herein by reference.)

Based on this principle, a dispersancy test was designed to testeffectiveness of the polymer to dispersant soot particles using aPhysica MCR 301 Rheometer (Anton Parr). A sooted oil have 4.3 wt. % sootwas generated from a fired diesel engine using a lubricating fluid thatcontains no dispersants. In this test, the sooted oil was then toptreated with a certain amount of polymers and then tested by a shearrate sweep in the rheometer with a cone on plate to look forNewtonian/non-Newtonian behavior. Test temperature was 100° C. and thetest top plate is CP50-1 (Anton Parr). A profile of viscosity and shearrate was recorded, and the results may be seen in FIG. 1.

As shown in FIG. 1, the untreated sooted oil (Curve A containing nodispersant) showed a curve of decreasing viscosity with increasing shearrate, which means that it is a shear thinning (non-Newtonian) fluid andthe soot is agglomerating. The higher viscosity at lower shear is a signof soot agglomeration. About 1.5 weight percent of the inventive polymerfrom Example 1 in the same sooted oil, on the other hand, exhibitedrelatively constant viscosity versus shear rate (Curve B). Furthermore,viscosity at low shear is lower than for Curve A. These results showthat Example 1 effectively disperse the soot particles at the treat rateused (1.5 weight percent).

The product polymer also has good elastomer compatibility up to 10% neatpolymer treat, as shown in Table 4. The invented polymer of Example 1was tested for elastomer compatibility in a reference fluid as listed inTables 3 and 4 below at 0, 2, 5, 10 wt % on neat polymer basis (noteExample 1 has a polymer content of about 45.5 wt % in the formedadditive concentrate). A fluoroelastomeric rubber was cut intobone-shaped pieces with a Type L die. The rubber pieces were thenimmersed in 30 mL scintillation vials containing about 22 grams of theoil composition of Table 3 to be tested. The vials were covered withfoil and placed in a 150° C. oven for seven days. After seven days, thevials were drained and the rubber pieces were blotted to remove excessoil. An elongation rupture test was conducted on each of the rubberpieces both before and after fluid soaking using an Instron and theresults are recorded in Table 4. As can be seen, even at very highpolymer treat rate (neat polymer at 10.0 wt %), the seal performance isstill excellent. This test shows that the amine capping of the OCP ofExample 1 improves the negative effect of the primary amine onelastomeric seals.

TABLE 3 Fluid component wt % Invented polymers (see Table 4) Dispersants4.0 Antioxidant 1.25 Metal detergents 1.18 Zinc dihydrocarbyldithiophosphates 0.47 Anti-wear agent 0.09 Pour point depressants 0.05Antifoam agent 0.005 Friction modifier 0.02 Base oils Balance

TABLE 4 Wt % of Neat Polymer from Pass >55% Pass >50% Example 1 Avg ER %Avg TS % 0 −48.21 −40.19 2 −54.11 −43.97 5 −52.27 −45.92 10 −54.11−47.11

In Table 4, Avg ER % is the average elongation to rupture compared tothe rupture elongation before immersion in the fluid. Likewise, Avg TS %is the reported tensile strength from the Instron at rupture compared tothe reported tensile strength rupture before immersion in the fluid.

Example 2 Maleated Medium Molecular Weight OCP Reacted with PolyetherDiamine then Capped with Naphthalic Anhydride

An ethylene propylene copolymer (Mn=22000, 20.10 wt % of reaction mass),a 110N base oil (9.03 wt % of reaction mass), and maleic anhydride (0.51wt % of reaction mass) were charged into a two-neck round bottom flaskequipped with a condenser and a Dean Stark apparatus under a nitrogenblanket. The flask was heated to 165° C. and held for 1 hour to ensuregood dissolution of the polymers. After complete dissolution, dicumylperoxide (0.077 wt % of reaction mass) was charged to the flask, heldfor 30 minutes, and followed by another dicumyl peroxide addition (0.077wt % of reaction mass). The resulting mixture was allowed to react for 1hour. After the reaction was complete, the flask was heated to 230° C.under a vacuum of 25 Hg for 4 hours to remove unreacted maleicanhydride. A Group II base oil (Phillip66 110N, 50.72 wt % of reactionmass) was added to the flask and the reaction temperature was set to165° C. A polyether diamine (Jeffamine D2000, Huntsman) was then addedto the flask and the flask was kept at a temperature of 165° C. for 2hours. A dispersion of 110N base oil (8.42 wt % of reaction mass) andnaphthalic anhydride (1.08 wt % of reaction mass) was prepared and addedto the reaction mixture. The resulting mixture was held at 165 C for 4hours to provide the final product, which had a kinematic viscosity at100° C. of 383.5 cSt. This Example shows a method using sequentialaddition of reactants.

It is to be understood that while the additives and lubricant of thisdisclosure have been described in conjunction with the detaileddescription thereof and summary herein, the foregoing description isintended to illustrate and not limit the scope of the disclosure, whichis defined by the scope of the appended claims. Other aspects,advantages, and modifications are within the scope of the claims. It isintended that the specification and examples be considered as exemplaryonly, with a true scope of the disclosure being indicated by thefollowing claims.

What is claimed is:
 1. An olefin copolymer viscosity modifier comprisingthe reaction product of a) an acylated olefin copolymer including anolefin copolymer having grafted thereon through a free radical graftreaction from 0.10 to 0.80 acyl groups per 1,000 number averagemolecular weight units of olefin copolymer and wherein the olefincopolymer has a number average molecular weight of between about 500 and40,000; b) a polyamine compound of Formula I:

 and c) a dicarboxylic acid or anhydride thereof, which can react with afree primary amine of Formula I to produce a ring moiety A

wherein X is a C₂ to C₅₀ alkylene linker unit wherein one or more carbonunits are optionally and independently replaced with a bivalent moietyselected from the group consisting of —O—, —NR′—,—NR′—, —C(O)—, —C(O)O—,—C(O)NR′, and wherein each X is optionally and independently substitutedwith one or more R″ substituents; each R′ is selected from the groupconsisting of hydrogen, C₁₋₆ aliphatic, phenyl, or alkylphenyl; and eachR″ is independently selected from the group consisting of C₁₋₆aliphatic, C₃₋₇cycloalkyl, a 3-7 membered heterocycloalkyl, heteroaryl,and phenyl, wherein R″ is optionally substituted with halo, cyano,amino, hydroxyl, —OR′, —C(O)R′, —C(O)OR′, or —C(O)NR′₂.
 2. The viscositymodifier of claim 1, wherein X is a polyalkylamine unit of the formula,-(alkylene-NR′)_(n)-alkylene-, and wherein the alkylene moieties areC₁-C₆ branched or straight alkylene moieties, and n is an integer from 1to
 20. 3. The viscosity modifier of claim 1, wherein X is a polyalkyleneglycol unit of the formula, -(alkylene-O)_(m)-alkylene-, and thealkylene moieties are C₁-C₆ branched or straight alkylene moieties, andm is an integer from 1 to
 50. 4. The viscosity modifier of claim 1,wherein the olefin copolymer is a copolymer of ethylene and an alkylenehaving 3 to 18 carbon atoms.
 5. The viscosity modifier of claim 4,wherein the olefin copolymer has a number average molecular weight ofabout 3,000 to about 20,000.
 6. The viscosity modifier of claim 1,wherein the acyl groups grafted on to the olefin copolymer are obtainedfrom acyl reactions that include at least one carbon-carbon double bondand further comprise at least one carboxylic acid and/or dicarboxylicanhydride group.
 7. The viscosity modifier of claim 6, wherein theolefin copolymer has grafted thereon from 0.2 to 0.5 acyl groups per1000 number average molecular weight units of olefin copolymer.
 8. Anadditive concentrate comprising: a base oil diluent; and a highlygrafted, multi-functional olefin copolymer viscosity modifier comprisingthe reaction product of a) an acylated olefin copolymer comprising anolefin copolymer having grafted thereon through a free radical graftreaction from 0.10 to 0.80 acyl groups per 1000 number average molecularweight units of olefin copolymer and wherein the olefin copolymer has anumber average molecular weight of between about 500 and 40,000; b) apolyamine compound of Formula I:

 and c) a dicarboxylic acid or anhydride thereof, which can react with afree primary amine of Formula Ito produce a ring moiety A

wherein X is a C₂ to C₅₀ alkylene linker unit wherein one or more carbonunits are optionally and independently replaced with a bivalent moietyselected from the group consisting of —O—, —NR′—, —NR′—, —C(O)—,—C(O)O—, —C(O)NR′, and wherein each X is optionally and independentlysubstituted with one or more R″ substituents; each R′ is selected fromthe group consisting of hydrogen, C₁₋₆ aliphatic, phenyl, oralkylphenyl; and each R″ is independently selected from the groupconsisting of C₁₋₆ aliphatic, C3-7 cycloalkyl, a 3-7 memberedheterocycloalkyl, heteroaryl, and phenyl, wherein R″ is optionallysubstituted with halo, cyano, amino, hydroxyl, —OR′, —C(O)R′, —C(O)OR′,or —C(O)NR′₂.
 9. The additive concentrate of claim 8, wherein X is apolyalkylamine unit of the formula, -(alkylene-NR′)_(n)-alkylene-, andwherein the alkylene moieties are C₁-C₆ branched or straight alkylenemoieties, and n is an integer from 1 to
 20. 10. The additive concentrateof claim 8, wherein X is a polyalkylene glycol unit of the formula,-(alkylene-O)_(m)-alkylene-, and the alkylene moieties are C₁-C₆branched or straight alkylene moieties, and m is an integer from 1 to50.
 11. The additive concentrate of claim 8, wherein the acyl groupsgrafted on to the olefin copolymer are obtained from acyl reactants thatinclude at least one carbon-carbon double bond and further comprise atleast one carboxylic acid and/or dicarboxylic anhydride group.
 12. Theadditive concentrate of claim 8, wherein the concentrate includes about10 to about 60 weight percent of the highly grafted, multi-functionalolefin copolymer viscosity modifier in the base oil diluent.
 13. Alubricating oil composition comprising: a major amount of a base oil;and a highly grafted, multi-functional olefin copolymer viscositymodifier comprising the reaction product of a) an acylated olefincopolymer comprising an olefin copolymer having grafted thereon througha free radical graft reaction from 0.10 to 0.80 acyl groups per 1000number average molecular weight units of olefin copolymer and whereinthe olefin copolymer has a number average molecular weight of betweenabout 500 and 40,000; b) a polyamine compound of Formula I:

 and c) a dicarboxylic acid or anhydride thereof, which can react with afree primary amine of Formula Ito produce a ring moiety A

wherein X is a C₂ to C₅₀ alkylene linker unit wherein one or more carbonunits are optionally and independently replaced with a bivalent moietyselected from the group consisting of —O—, —NR′—, —NR′—, —C(O)—,—C(O)O—, —C(O)NR′, and wherein each X is optionally and independentlysubstituted with one or more R″ substituents; each R′ is selected fromthe group consisting of hydrogen, C₁₋₆ aliphatic, phenyl, oralkylphenyl; and each R″ is independently selected from the groupconsisting of C₁₋₆ aliphatic, C₃₋₇ cycloalkyl, a 3-7 memberedheterocycloalkyl, heteroaryl, and phenyl, wherein R″ is optionallysubstituted with halo, cyano, amino, hydroxyl, —OR′, —C(O)R′, —C(O)OR′,or —C(O)NR′₂.
 14. The lubricating oil composition of claim 13, wherein Xis a polyalkylamine unit of the formula, -(alkylene-NR′)_(n)-alkylene-,and wherein the alkylene moieties are C₁-C₆ branched or straightalkylene moieties, and n is an integer from 1 to
 20. 15. The lubricatingoil composition of claim 13, wherein X is a polyalkylene glycol unit ofthe formula, -(alkylene-O)_(m)-alkylene-, and the alkylene moieties areC₁-C₆ branched or straight alkylene moieties, and m is an integer from 1to
 50. 16. The lubricating oil composition of claim 13, wherein theolefin copolymer has a number average molecular weight of about 3,000 toabout 20,000.
 17. The lubricating oil composition of claim 13, whereinthe lubricating oil composition includes about 0.01 to about 10 weightpercent of the highly grafted, multi-functional olefin copolymerviscosity modifier.